Alarm and annunciator system



April 1962 R. J. MARMORSTONE 3,028,585

ALARM AND ANNUNCIATOR SYSTEM 2 Sheets-Sheet 1 Filed March 28, 1955INVENTOR.

.57 W 5 M221) A 16L April 1962 R. J. MARMORSTONE 3,028,585

ALARM AND ANNUNCIATOR SYSTEM 2 Sheets-Sheet 2 Filed March 28, 1955 ur! zUnited States Patent 3,028,585 ALARM AND ANNUNCIATOR SYSTEM Robert J.Marmorstone, Chicago, Ill., assignor, by mesne assignments, to I51,Incorporated, Los Angeles, Caliti, a corporation of Delaware Filed Mar.28, 1955, Ser. No. 497,149

Claims. (Cl. 340-213) This is a continuation-in-part of applicationSerial No. 414,704, filed March 8, 1954- by Albert P. Sperry and RobertJ. Marmot-stone on an Alarm and Annunciator System, now abandoned.

This invention relates to annunciator systems and more particularly toan annunciator system which includes relay apparatus usable with eithernormally closed or normally open signal contacts.

Annunicator systems usually comprise a condition-responsive element,such as a thermocouple or the like, associated with each test point orvariable to be monitoredand which includes a pair of cooperatingelectrical contacts which open or close when the associated test pointor variable is normal and which respectively close or open when theassociated test point or variable is abnormal. Each set of signalcontacts or condition-responsive contacts are associated with relaycircuitry which in turn control various audible and visual alarmannunciator units. Where a large number of test points are involved,such as is common in power plants and other large industrialinstallations, the various relay circuits directly controlled by thesignal circuits are tied into common busses wherever possible andbrought to a central indicatingand control panel where, by means ofindicating lights or the like, an operator may monitor the various testpoints from a central location and may perform variou control operationswith respect thereto.

For example, it is common to include on such control panel a separatelight for each test point which lights up when the associated test pointbecomes abnormal and an audible alarm common to all of the test pointswhich is sounded the instant any test point becomes abnormal. Thisattracts the operators attention to a particular part of the controlpanel which indicates the location of the abnormality. An acknowledgepush button is generally provided which de-energizes the audible alarmso that the alarm may be operated by the initiation of other abnormalconditions for other test points in the system.

Certain industrial applications, for example, power plant applications,prefer to utilize normally open signal contacts to minimize drain on thebattery system used for energizing the annunciator circuits; on theother hand, many chemical and other industries prefer to utilizenormally closed alarm contacts where the circuit in which the contactsare located draw current in their normal position. Heretofore, the relayapparatus which con trolled the visual and audible annunciator unitswere variously designed for signal contacts having normally open andnormally closed contacts, respectively. Inaccordance with thisinvention, the same relay apparatus produces identical operation of thevisual and audible annunciator units when used on normally open ornormally closed contacts. This results in standardization of the"components making up the annunciator system.

The foregoing and other features of the invention will be understoodmore clearly upon a study of the description which follows withreference to the drawings appended hereto. It should be understood thata number of specific features are here described and illustrated asbeing preferred for certain purposes, which may be omitted withoutdeviating from the broader aspects of theinvention.

In the drawings:

FIG. 1 is a schematic diagram of one embodiment of the invention;

FIG. 2 is a modified form of the embodiment of FIG. 1; and

FIGS. 3 and 4 are across the line diagrams of a third embodiment of theinvention with diiferent jumper connections to adapt the same relayapparatus for use on normally open and normally closed contacts.

Referring first to FIG. 1: I

A panel or cabinet 10 is provided to interconnect a series of signalswitches 11A, 11B, etc., with a corresponding' series of visual alarmannunciators 24A, 24B, etc. forming part of an alarm light cabinet orpanel 25,- preferably close to or even integral with the basic panel orcabinet 10. Each signal switch 11A, 11B',etc., is suitably incorporatedin or-associated with a machine or field unit to be protected by thealarm system, by well known thermostatic means, liquid pressureresponsive means or equivalent apparatus (not shown).

Animportant feature of the present system is that any one, more or allof the signal switches 11A, 11B, can be normally open or closed and thatnevertheless no modi fication whatsoever is required in the structureand arcooperates with the normally open or normally closed signal switch11A, 313', etc.

At a suitable location, usually at a central point in the plant, anaudible alarm device such as a loud horn 12- is provided in order toalert practically the entire plant personnel whenever any one of thesignal switches 11A, 11B, etc., changes from its normal (open or closed)to its abnormal (closed or open) position. By means of the three relayconstruction of the plug-in unit, such horn operation is initiated inthe starting or alerting phase of each alarm program, and also in areturn alarm or allclear sounding phase thereof, regardless whether thealarm initiating signal switch 11A, 113, etc., is normally openornormally closed; no modification of the wiresystem whatsoever beingrequired and utilized in this connection.

At or near said central location there is also'provided a push-buttonstation 13 in order to allow the plants'uperintendent to acknowledge thealarm alert and silence the horn, and also suitably to modify the otheror visual alarm announcements, caused by the alerting phase, as soon asthe alert has been noted and remedial action started. For such andrelated purposes the push-button station contains a push button 15, theinterconnections of which-will best be explained hereinafter. It may benoted at this point that the same push button also serves to reset thesystem in its normal position when a return alert hasbeen sounded andvisually indicated, which last mentioned sounding and visual indicationis occasioned by the return of the alarm initiating signal switch. 11Aor 1113, etc., into its normal (closed or open) position.

Thus the complete alarm program according to the present system, whichcan be caused by any of the nor mally open or normally closed signalswitches 11A, 11B moving into abnormal and then back to normal position,comprises the following phases:

(1) A signal switch 11A, 1113", etc., moves into abnormal position; thiscauses transmission of audible alerting signals to the plant and controlstation through the horn 12 and of a corresponding visual alertingsignal to the control station through the corresponding light unit 24A;the preferred visual indication of this phase being flashing of thislight unit (alert or alerting phase).

Patented Apr. 3, 1962 (2) The superintendent acknowledges the alert bydepressing the push button this causes transmission of a primary alarmmodifying signal to the plant by silencing the horn 12 and transmissionof a primary alarm modifying signal to the control station bymodification of the announcement at 24A, which at this time preferablybecomes steadily illuminated (acknowledged condition).

(3) The signal switch responsible for the original alert moves back tonormal position; this causes transmission of a new audible or all-clearsignal to the plant through the horn 12 and to the control stationthrough the aforementioned light unit which begins to flash again(return alert).

(4) The superintendent depresses the push button 15 again, which at thistime transmits final reset signals, different from those caused by thefirst depression of the push button. The horn is silenced again and theaforementioned alarm light unit at this time is extenguished (reset ornormal position).

For the detailed circuit analysis which follows, it may be assumed thatthe signal switch 11A is normally open and that the signal switch 11B isnormally closed.

The signal switch 11A, is interconnected with its corresponding lightunit 24A by a relay plug-in device 17A. Switch 11B is similarlyinterconnected by a relay unit 17B. These relay plug-in units 17A, 17B,etc., are identical with one another in every respect, as shown,although their starting switches 11A, 11B operate in manners basicallyopposite to one another as mentioned.

Eight bus wires are shown within the panel or control box 10. Inaddition, there is provided a hot wire H which need not be connected tothe different relay plug-in units 17A, 17B, etc, and which accordinglyis shown outside the panel, thereby limiting the system of bus wiresinstalled on the panel. This system comprisis: A horn control wire R; alight flashing wire F; a lamp test wire T; an acknowledgment and resetcontrol wire C; and a neutral wire N. These five bus wires C, R, F, Tand N are the only bus wires installed within the cabinet which areutilized in the operation to be described hereinafter. In the interestsof standardization, which a slightly amplified system or group ofsystems to be described hereinafter, there are also shown bus wires K,PR and RR, on the control panel, which can be disregarded for presentpurposes. However, it is preferred to interconnect them with thecorresponding terminals on the plug-in sockets, in manner identical withthat to be described hereinafter in connection with FIGURE 2; thematerial and labor involved in such standardization being insignificantin cost and conducive to much greater simplicity and safety in massproduction and mass testing.

For the flashing operation mentioned above, there is provided a flasherswitch 178 interposed between the neutral wire N and the light flashingwire F, and operated by a flasher motor 17M which is connected inparallel with the horn 12, between the neutral wire N and the horn wireR. A flasher relay 17F is formed by this flasher switch and flashermotor and it is usually sufiicient to provide a single flasher relay ofthis kind for a very large number of individual alarm relay units 17A,178, etc., cooperating therewith.

The reset and acknowledgment control wire C is connected with the hotwire H through its push button 15 which is normally closed, therebynormally making this control wire the source of electric current for theentire system, together with the neutral wire N.

Coming now to the details of the branch circuits interconnecting theforegoing major parts of the alarm system, and referring particularly tothe branch ciruits associated with the normally open signal switch 11A:

The relay or plug-in unit 17A has eleven connector plugs, inserted incorresponding connector socket terminals, all of which are schematicallyshown at X-l to 4 X-11. Connected with these plugs the unit 17A hasthree relay coils A, B, and C, each of which has one terminal connectedwith the neutral wire N by the plug X4.

The other terminal of the coil A is connected by the plug X10 with oneside of the signal switch 11A, the other side of which is connected withthe hot wire H. A terminal Y-10A is interposed on this connection,between the plug X10 and the switch 11A, and similar terminals Y-ZOB,Y-10C, etc., are provided for the similar plugs X10 of the other relayunits 17, etc. The entire series of terminals Y-10A, Y-10B, etc., isincorporated in a single compact terminal unit Y, such as an insulatingstrip with suitable binding posts or the like, which preferably islocated in the back of the cabinet 10 at a conveniently accessible pointin order to facilitate installation, interconnection with differentlocations in the field, maintenance and checking.

The control wire C, through the connector plug X3, is connected withthree circuits, two of which have shunts. One of these circuits leads tothe free terminal of the coil B and has a normally open switch B1interposed thereon, and a normally closed switch A1 interposed on ashunt around B1. The second of the three circuits mentioned leads to thehorn wire R and has interposed thereon normally open switches B2 and C1in series. The last of the three circuits mentioned leads to the freeterminal of the coil C and has the normally open switch A2 thereon andthe normally open switch C2 on a shunt around A2.

It will be understood that all switches identified as A1, A2, etc., arelocated within the plug-in unit 17A and controlled by the coil A, andcorrespondingly all switches identified as B1, C1, etc., are similarlylocated and controlled by the corresponding coils B, C.

Connections to and for the lamp unit 24A are made through theaforementioned jack 20-9A which can be inserted either in acorresponding socket terminal of a socket 20-9 or in a socket 20-11;said sockets being interconnected with corresponding terminals X9 andX11 on the plug-in unit 17A. Two alternative connections are thusprovided, one of which is used in the present case where the signalswitch 11A is normally open, while the other is utilized in connectionwith the normally closed switch 113. The sockets 20-9 are used inconnection with the normally open signal switches 11A, etc., and theircorresponding relay units 17A, etc., whereas the sockets 20-11 are usedwith the normally closed signal switches.

In either case connections are made so that if desired, a single lamp,with a backlighted nameplate in front, can distinctively and clearlyindicate the several states or phases of any alarm initiated by thecorresponding switch and relating to a clearly identified plant unit.

For these purposes the lamp terminal plug X9 connected with thecorresponding lamp through the socket 20-9 has two primary branchesconnected therewith within the relay plug-in unit 17A, containingrespectively normally open and normally closed portions A3 and A4 of adouble-throw switch. The normally open portion A3 in turn has twobranches within the unit 17A containing respectively normally open andnormally closed portions B3 and B4 of another double-throw switch. Thelatter portions are connected respectively through the connector X7 withthe flasher bus F and through the connector X4 with the neutral wire N.The normally closed portion A4 of the first mentioned double-throwswitch has another pair of branches in the relay unit, containingrespectively the normally open and normally closed parts C3, C4 of stillanother double-throw switch, connected respectively by the plugs X7 andX5 with the flashing wire F and the testing wire T.

The interconnection of the common terminal X9 with the correspondinglamp 24A could theoretically be obtained by a terminal strip arrangementsimilar to that shown at Y for the corresponding signal switchcorrectrons. However, there is a practical difierence between the signalswitch and signal lamp connections. The former inherently requireindividual hook-up arrangement with remote field stations, whereas thelatter are desirably united in a compact panel or a lamp bezel adjacentthe panel 10, and it is frequently desirable to establish, separate andre-establish connections between the relay and lamp panels 19, 25, fortesting and other purposes. It is for this reason that the use of jackor plug connectors 20-91%, etc., is preferred at this point. It willalso be noted that the corresponding sockets 2tl9, 2041 areinterchangeable with corresponding sockets shown in the co-pendingapplication Serial No. 312,821.

The system of branch circuits in the unit 17A, connected with the switch11A and lamp 24A, is completed by a circuit and shunt around the sameconnected with the free terminal of the coil C. Said circuit containsthe normally open switch A2 while the shunt contains the normally openswitch C2. Connection is thus made to the acknowledgment and resetcontrol wire C, through the terminal X3.

The horn 12 and control switch 15 as well as a lamp test switch 16, tobe described hereinafter, are desirably connected with the wiring of thepanel in manners similar to that used for the connections of the signalswitches 11A, 11B, etc., that is, through a terminal strip W arranged tofacilitate individual field connections of permanent nature, asindicated for instance at WN, WR for the horn 12.

The details of the alternate lamp circuit and its terminal X31,connected with the normally closed signal switch 115 and correspondinglamp 24B, will be described hereinafter. At the present point it may benoted that the panel 1% has, in addition to the bus wires describedabove, a row of identical plug-in devices 17A, etc., the system of lampplug-in sockets 28-9, 23-11, the flasher relay 17F, a pair of terminalstrip units W and Y for connection with the alarm equipment 12, 15, 16and the signal equipment 11A, 118 respectively, and of course a seriesof plug-in sockets, diagrammatically shown at X1, etc., for the plug-inrelay units 17A, 17B, etc.

OBERATEON WlTH NORMALLY OPEN SIGNAL SWITCHES The signal switches 11A,etc., as mentioned are normally open. The corresponding jacks 209A,etc., as mentioned, are inserted in the sockets 209.

The corresponding lamp units 24A, etc., are normally off. The plant-wideaudible annunciator 12 of course is normally or In the relay units 17A,etc., the coils A are connected and disconnected through the signalswitches 11A; the coils B are normallyenergized through normally closedswitches A1 and self holding through switches B1; and the coils C areconnectable through normally open switches A2 and self holding throughswitches C2; the circuits of connecting and self-holding switches A1,B1, A2 and C2 being controlled by the push button 15.

Accordingly it will be seen'tha't as a result of the normally opencondition of the signal switch 11A, the coil A is normallytie-energized; the coil B is normally energized through Al; and the coilC is normally de-energized.

As a further result it will be seen that the bus wires R and F arenormally de-energized, all connections thereof containing at least onenormally open switch C1, A3 and C3. Thus neither horn actuation norflashing of lamp 24A, etc., occurs normally. Nor is lamp 24A steadilyilluminated in the normal position, the remaining connections thereofbeing open at B4 and 16 respectively.

Upon the occurrence of an abnormal condition in the protected plant unitor machine, the signal switch 11A closes. This energizes the coil A,this in turn closes the switch A2 thereby energizing the coil C. Theenergized coil B remains energized at B1. Thus all coils A, B and C arenow energized. Due to the closing of the switch C1 and the switch B2,the horn wire R is energized and the horn 12 begins to sound. Inparallel therewith the flasher motor 17M begins to operate. The switchesB3 and A3 connecting the lamp 24A with the flashing bus wire F are nowclosed, and the lamp 24A begins flashing (a steady illumination of lamp2413, etc., may simultaneously exist in connection with another signalswitch 118', etc., but no interference will occur, the flashingconnections and steady illuminating connections of the lamps being madethrough separate wires F and N and separate relay switches asdescribed).

Acknowledgment of the alarm, by momentarily depression of the pushbutton switch 15, momentarily de-energizes the control bus C and therebythe plugs X3. This results in momentary de-energization of the coils Band C. The coil B remains de-energized, its self-holding switch B havingopened and its starting switch A1 being held open by the energized coilA. The coil C is promptly re-energized upon release of the push button15, through the switch A2 which is held closed by the coil A. Thus thecoils A and C are energized and the coil 33' is de-energized during theacknowledged alarm condition. The horn sounding and flashing connectionsare eliminated thereby as described, whereas thelamp 24A is nowconnected to the neutral wire N through the switches A3 and B4 and tothe hot wire H through the reclosed acknowledgment switch 15. Thusduring the acknowledged alarm condition further disturbance of the plantpersonnel by sounding of the horn is avoided whereas the lamp 24Acontinues to indicate the existence and exact location of a dangercondition.

When that condition has been removed, the signal switch 11A opens again,thereby de-energizing the coil A again. This re--energizes the coil Bthrough the normally closed switch A1, while the coil C remainsenergized through the seal-in switch C2. Thus the return.

alarm position which now follows is characterized by deenergization ofthe coil A and energization of the coils B and C. The one bus F andflasher relay 17F are connected again, as before; the horn sounds andthe lamp 24A shows a return alert or all-clear signal for the unitpreviously alerted, while the previous steady illumination of the lamp24A is broken at B4.

Renewed operation of the push button 15 again m0- mentarily de-energizesthe coils B and C. This time the coil B is re-energized through thenormally closed switch A1 while the coil C still is de-energized at A2.Thus the normal position of the system, wherein only the coil B isenergized, is re-established and all annunciators are off.

It will thus be seen that the sequence of operations described up tothis point can be summarized as follows:

Operation With Normally Open Signal Switches Phase A B 0 24A 12 Alert EE E Flashing E Acknowledged Alarm E I) E Steady... D Return Alert D E EFlashing" E Reset (Normal) D E D On D It will be understood that in thischart the letter D signiiies dc-energized while the letter E signifiesenergized.

OlERATlON WITH NORMALLY CLOSED SIGNAL SWICTHES relay unit 17A, andidentically in the unit 17B utilized in the present instance, twocircuit branches having interposed thereon the normally closed andnormally open portions A and A6 of a double-throw switch controlled bythe coil A. The branch AS in turn has two branches having interposedthereon the normally open and normally closed sides C5 and C6 of adouble-throw switch operated by the coil C, connected respectivelythrough plugs X-7 and X-4 with the flashing and neutral wires F, N. Theother branch A6 has two branches with the normally open and normallyclosed sides B5, B6 of a double-throw switch controlled by the coil B;connected respectively through the terminals X-7 and X-5 with theflashing and test wires F, T. It may be noted that the connections aresubstantially the reverse of those shown at X-9. Thus it will beunderstood without further detailed analysis of the correspondingcircuits that with the present'method of plugging in at 20-11 andwithout change as to the horn 12, there is obtained the following:

Operation With Normally Closed Signal Switches Testing of the difierentlamps 24A, 245, etc., whether connected at 20-9 or 29-11, isconveniently effected by depression of the push button 16, which asshown is interposed between the neutral wire N and the test wire T. Ifsuch depression of the push button occurs during an otherwiseunenergized condition of the lamps, such as the normal position of thesystem, it energizes the lamps 24A connected at 20-9, through theswitches C4 which in this method of interconnection are normally closed.It likewise connects the lamps 24B plugged in at 20-11 through theswitches B6, which in this latter condition are normally closed. Thusthere is provided a convenient single testing operation, regardless ofthe other variations of announcements as described.

THE MODIFICATION OF FIGURE 2 The jacks 20-9A, 20-9B, etc., can bereplaced by the poles of single-pole double-throw switches 208A, 265B,etc., preferably of the toggle switch type, so that it is not evennecessary to modify the insertion of jacks and corresponding cords whenchanging over from normally open to normally closed arrangements as at11A, 1113'. In this modification it is merely necessary to provide on ornear the panel 10 a double-throw switch 205A, etc. for each annunciatorlight 24A, and to interconnect the common leg or permanently connectedterminal of each switch 208A, etc. with the respective light 24A, etc.(in the same manner as the sockets 20-9 or 28-11 are connected therewithby the jacks 20-9A, etc. in FIGURE 1). The sockets 20-9, 20-11 can beomitted; the wires C-9, C-11 from the relay plug-in terminals X-9, X-llcan be connected with the alternate legs or terminals of thecorresponding switches 208A, etc., with or without terminal strips20-9A, 20-11A interposed, depending on whether the switches are on oraway from the panel 10.

THE MODIFICATION OF FIGURES 3 AND 4 In the embodiment of FIGS. 3 and 4,the same plug-in unit is utilized with normally open or normally closedfield contacts. However, the number of relays and the number of contactsper relay are reduced over the embodiment shown in FIGS. 1 and 2.Further, in the modification of FIGS. 3 and 4, the alarm light 24aremains fixed in place in the circuit when operating from normallyclosed or normally open field switches. Instead of relocating the alarmlight when changing from normally open to normally closed signalswitches, or vice versa, the jumper lead I L connected to the No. 8plug-in terminal of the plug-in unit 17a is relocated from its positionin connection with the H supply line where normally open field switchcontacts are utilized to connection with the N supply line (see FIG. 4)when used with normally closed field contacts. No other changes arerequired.

The same plug-in unit is usable with either normally open or normallyclosed signal switch contacts in the embodiment of FIGS. 3 and 4,because of the particular arrangement of the field signal contacts inthe circuit and because of the connection of the addition of a seriesresistor R in the A relay coil circuit between the N and H supply lines.In this embodiment, the field contacts, whether normally open ornormally closed, are connected between the H supply line and theterminal of the resistor R supply line and the terminal of the resistorR which is remote from the resistor terminal connected to the N supplyline. The resistor R and the field switch contacts are therefore alwaysin series across the supply line. When the jumper lead IL is connectedto the H supply line as shown in FIG. 3, where normally open fieldswitch contacts are used, the A relay coil is in parallel with the fieldswitch contacts so that the A relay coil is de-energized upon theinitiation of an abnormal condition. On the other hand, where the jumperlead IL is connected with the N supply line as in the normally closedfield switch arrangement of FIG. 4, the A relay coil is in series withthe field contacts so that the opening of the field contacts in responseto an abnormal condition of a variable also results in thetie-energization of the A relay. The identical annunciating sequencetherefore exists whether the system is connected with normally opened ornormally closed field switch contacts.

Refer now to FIG. 3 for a more complete description of the circuitry. Asthere shown, each relay plug-in unit 17a has only two relays, namely analarm relay A and an acknowledgment relay B. The alarm relay A isconnected in a circuit extending from the N supply line through acurrent limiting resistor R, the No. 2 plug connector of the relay unit17a, the relay coil A, the No. 8 plug connector of the relay unit 17a,through the jumper lead JL connected with the H power line. The fieldcontacts 11A have one terminal connected to the H supply line and theother terminal connected in the line leading to the No. 2 plug-interminal of the plug-in relay unit 17a. The field contacts 11A aretherefore connected in shunt with the A relay coil so that upon theexistence of an abnormal condition of the variable which controls thefield contacts, the field contacts will close shunting out the A relaycoil from the supply line. The resultant de-energization of the A relayresults in the energization of the horn 12 and the flashing onindication of the alarm light 24A.

The energization circuit of the horn 12 can be traced from the N supplyline, through the born 12, the common R bus, the No. 6 plug-in terminalof a relay unit 17a, the normally open but then closed contacts B2 ofthe acknowledge relay coil B, the then closed normally closed contactsA2 of the alarm relay, the No. 3 plug-in terminal of the relay unit 17a,the common acknowledge bus C, and through the normally closedacknowledge push button switch 15 leading to the H supply line. Theexpression normally closed or open relay contacts means that the relaycontacts have these respective conditions when the associated relay isde-energized.

The energization circuit of the alarm light 24A can be traced from the Nsupply line through the interrupter contact 17111 of the flasher unit 17common flasher bus F, the No. 7 plug-in terminal of the relay unit 17a,the normally closed contacts A-S, the then closed normally open contacts13-4, the No. 1 plug-in terminal of relay unit 17a, the alarm light 24A,the common acknowledge bus C, and through the then normally closedacknowledge push button switch 15 leading to the H supply line. Theflasher contacts 17m) are active because the flasher motor 17m isconnected in parallel with the horn between the N supply line and thecommon horn bus R.

The energization circuit of the acknowledge relay B can be traced fromthe N supply line, the No. 4 plug-in terminal of the relay unit 170:,the acknowledge relay coil B, the then closed normally open holdingcontacts B 1, the No. 3 plug-in terminal of the relay unit 17a, thecommon acknowledge bus C, and through the normally closed push buttonswitch 15 leading to the H supply line.

When the operator is attracted by the sounding of the horn 12 hedepresses the acknowledge push button 15 which breaks the holdingcircuit of the B relay to deenergize the same. Release of theacknowledge push button 15 does not result in the re-energization or"the acknowledge relay B because the normally opened contacts Al inparallel with the B relay holding contacts B1 are open due to thetie-energized condition of the l A relay.

The de-energization of the B relay changes the flash ing indication or"the alarm light 24A to a steady-on condition and tie-energizes theaudible alarm 12. The latter occurs because the aforementioned normallyopen contacts B2 are then opened which interrupts the energizationcircuit of the audible alarm 12.

The alarm light 24A is in a steady-on condition because of theestablishment of an energization circuit extending from the N supplyline through the No. 4 plug-in terminal of relay unit 17A, the thenclosed normally closed contacts A7, the then closed normally closedcontacts E5, the alarm light 214A, the common acknowledge bus C andthrough the then closed acknowledge push button switch 15 leading to theH supply line. The circuit leading to the flasher bus F is interruptedbecause of the opening of normally open contacts B4 which connects withthe flasher bus through the then closed normally closed contacts A5.

Upon return to normal of the variable involved, the field contacts 11Awill open thereby re-energizing the alarm relay as the shunt circuitincluding the field contacts open.

The re-energization of the A relay efiects the re-energization of the Brelay as the normally open contacts A1 close. The B relay then seals inthrough its holding contacts B1. The audible alarm 12 is not sounded atthis time because the normally closed contacts A2 have opened. The alarmlight 24A is extinguished because of the opening of contacts A7 and B inone of the alternate energization circuit branches of the alarm light24A. The other branch of the energization circuit of the alarm light 24Ais unenergized because of the opening of normally closed contacts A5. 7

To test the operation of the alarm light 24A, the test push button 16 isdepressed which if the alarm light 24A is in operating condition willenergize through a circuit extending from the N supply line, the pushbutton 16', the common test bus T, the No. 5 plug-in terminal of therelay unit 17A, the then closed contacts A4 (normal operation isassumed), the then closed contacts E4, the N0. 1 plug-in terminal of therelay unit 17A, the alarm light 24A, the common acknowledge bus C, andthrough the then closed acknowledge push button switch leading to the Hsupply line.

The circuit shown will give an alarm also upon failure of either the Aor B relay coils. Since the A relay coil is normally energized, failureof this coil will result in contacts A3 which shunt the normallyopencontacts B2 and the normally closed contacts A2 in the energizationcircuit of the audible alarm 12. With the A relay energized, failure ofthe B relay will result in the energization of the audible alarm becauseof the establishment of this new branch circuit upon the closing of thenormally closed contacts B3 in series with the then closed normally opencontacts A5.

Failure of the B relay during energization of the A relay will alsoresult in the flashing of the alarm light 24A due to the establishmentof an energization circuit therefor extending from the N supply line,the interrupter Contact 17mf of the flasher motor unit, the commonflasher bus F, the No. 7 plug-in terminal of the relay plug-in unit 17A,the then closed normally open contacts A6, the normally closed contactsB5, the alarm light 24A, the common acknowledgment bus C and through thenormally closed push buttin switch 15 leading to the H supply line.

As previously stated, it is unnecessary to review the operation of theannunciator circuit when used with n0rmally closed field contactsbecause in the latter situation opening of the field contacts during anabnormal condition results in the de-energization of the alarm relay Asince the field contacts are then in series with the A relay coil due tothe relocation of the jumper lead IL. The relay apparatus thus operatesin the same manner whether normally open or normally closed contacts areused. I

It should be understood that numerous variations may be made in thecircuitry above described without departing from the spirit of theinvention.

I claim:

1. Annunciator apparatus for monitoring a series of field stations, asignal switch for each field station adapted to assume a normal and anabnormal position, respective annunciator means associated with saidsignal switches for indicating the position of the corresponding signalswitch, manually operable control switch means for modifying theindication of said annunciator means, relay control apparatus for eachsignal switch and associated annunciator means, each relay controlapparatus having signal switch connecting terminal means adapted forselective connection to signal switches having normally closed ornormally open contacts, a first set of annunciator connecting wiresleading'from said respective relay control apparatuses, a second set ofannunciator connecting wires leading from said respective relay controlapparatuses, means for selectively connecting said respectiveannunciator means to one or the other of said sets of annunciatorconnecting wires depending on whether said signal switch connectingterminal means are connected to normally open or normally closed signalswitches, means including means interconnecting said first set ofannunciator connecting wires with their associated relay controlapparatus for providing a given sequence of respective annunciatorindications on the associated annunciator means during the followingsequence of operation of a normally closed signal switch and saidcontrol switch means:

(a) opening of such signal switch,

(b) manual operation of said control switch means,

(0) closing of said signal switch, and then (d) manual operation of saidcontrol switch means, and means interconnecting said second set ofannunciator connecting wires with their associated relay controlapparatus for providing said same sequence of annunciator indications onthe associated annunciator means in the same order during the followingsequence of operation of a normally open signal switch and said controlswitch means:

(a) closing of such signal switch (b) manual operation of said controlswitch means (c) opening of said signal switch, and then (d) manualoperation of said control switch means.

2. Apparatus as described in claim 1 wherein said selective connectingmeans comprise a number of doublethrow switch contacts respectivelyconnected with the corresponding annunciator means and adapted to makealternate connection with said terminals of the associated pair ofconnecting terminals.

3. Apparatus as described in claim 1 wherein said connecting terminalsand selective connecting means are cooperating plug and socketconnectors whereby the annunciator means associated with each signalswitch may be selectively connected with either terminal of theassociated pair of connecting terminals.

4. Apparatus as described in claim 1 wherein each relay controlapparatus comprises three separately energizable and de-energizablemulti-pole relays of the two position type, and circuit meansinterconnecting said relays and their associated contacts with saidsignal switch, control switch means and annunciator means for providingat least four diiferent indications whether the signal switch isnormally open or normally closed.

5. Apparatus as described in claim 4 wherein there is provided means forenergizing a pair of the relays to provide one of the four indications;means for energizing one of the relays to provide a subsequentindication; means for energizing all three relays to provide the nextsubsequent indication; and means for energizing another pair of relaysfor the fourth indication.

6. Apparatus as described in claim 5 wherein the control switch means isconnected in common with all of said relays.

7. Apparatus as described in claim 5 wherein said three relays are soconnected that successive reversals of the corresponding signal switchand intermediate operations of the control switch means provide thefollowing sequence:

A B G E E E E D E D E E D E D where A, B and C are the three relaycoils, the A relay coil being arranged to respond directly to a changein position of the associated signal switch, D means deenergized, and Emeans energized.

8. Apparatus as described in claim 5 wherein said three relays are soconnected as to provide the following sequence when connected to one ofsaid types of signal switches:

U'dmm t random in drama Q by initial reversal of the correspondingsignal switch, subsequent momentary operation of the control switchmeans, subsequent return of the signal switch to the original positionand final momentary operation of the control switch means, respectively;A, B and C meaning the three relay coils, D meaning de-energized, and Emeaning energized.

9. In an annunciator system, an alarm relay and an energization circuitfor said alarm relay in which signal contacts are to be interposed forcontrolling the energization and de-energization of the alarm relay,second and third control relays and respective energization circuitstherefor, annunciator means and an energization circuit therefor,acknowledge switch means and contacts of said alarm relay in theenergization circuit of said second and third relays and adapted tode-energize said second relay upon actuation of said acknowledge switchmeans when the alarm relay is in one of its positions and adapted totie-energize the third relay when the alarm relay is in the other one ofits positions, the energization circuit of said annunciator means havingtwo alternate branches each containing contacts of all three relays, oneof said branches being arranged for operation with normally closedsignal contacts and the other branch being arranged for operation withnormally open signal contacts, and terminal means for selectivelyconnecting said annunciator means in either one of said branch circuits.

10. In an annunciator system comprising a set of signal contacts adaptedto assume opposite positions when the associated variable is normal andabnormal, respectively, and an alarm relay and an energization circuittherefor in which said signal contacts are interposed for controllingthe energization and de-energization of the alarm relay, second andthird control relays and means for holding the same in one of theirstates of operation, respective energization circuits for said secondand third relays, said alarm relay having a set of contacts in theenergization circuit of said second relay which operate the same intoits holding position when the alarm relay is in one of its positions,the alarm relay having contacts in the energization circuit of the thirdrelay which operates the third relay into its holding position when thealarm relay is in the opposite position, annunciator means and anenergization circuit therefor, the energization circuit of saidannunciator means having two main branches in which the annunciatormeans may be selectively interposed, each of said branches includingcontacts of said alarm relay and said second relay arranged to energizesaid annunciator means when the alarm relay is actuated to one of itspositions and also having other contacts of said alarm relay andcontacts of said third relay arranged to energize the annunciator meanswhen said alarm relay is actuated to the other one of its positions, oneof said main branches having contacts of said second relay arranged in acircuit which modifies the signal of the annunciator means when thesecond relay is in its non holding position, and the other main branchcircuit including contacts of said third relay which are arranged tomodify the signal of the annunciator means when the third relay is inits non-holding position, and acknowledge switch control means in theenergization circuits of said second and third relays and arranged toactuate said relays momentarily to their non-holding positions.

References Cited in the file of this patent UNITED STATES PATENTS1,640,325 Janson Aug. 23, 1927 1,686,492 Janson Oct. 2, 1928 1,920,153Clokey July 25, 1933 2,600,132 Seaton June 10, 1952 2,813,263 WarrenNov. 12, 1957

